Monday, October 12, 2009

Quantum Numbers

Pauli Exclusion Principle: no two electrons can have the
same set of four quantum numbers

1st - Principle QN


2nd - Orbital QN


3rd - Magnetic QN


4th - Spin QN


n = 1,2,3...7

l goes from 0 to n-1within an energy level

l values = 0 (for s), 1(for p), 2 (for d), 3 (for f) sublevels

Values of ml go from +l to - l , which gives 2l + 1 number of valueshas 2 values:
+1/2 (spin up) and -1/2(spin down)
1. measures the average distanceof the e- from the nucleus1. indicates the shape of the orbital ( set of probable locations of the e- )1. identifies the direction the e-orbital has around the nucleus1. identifies the "spin" orrotation of the e- about its own axis
2. different values of n mean different energy levels2. diff. values of l mean diff sublevels. In a sublevel all the e- have nearly the same energy.2. specifies the e- orbital in which the e- is located within a sublevel.2. shows that each orbitalcan contain only 2 e-
3. different values of n mean relatively large differences in the energies of the e-s

3. different sublevelswithin the same level may have moderately large differences in energy.

3. different values of ml mean little difference in energies of the e-3. the direction of spin is either in one direction or the other
4. the smallest avgerage distance and the lowest energy occurs when n = 1; each increase in n increases those quantities.4. within any level, the lowest energy sublevel is s, then p, then d, then f.4. the number of possible values of ml within a sublevel idenities how many e- pairs that the sublevel can hold4. when 2 e- (in an atom) have the same set of QN except for ms, then these e-are called an e- pair
5. the number of e- possible in a level is 2n25. the number of possible values of l for a level is equal to the value of n 5.these e- within an e- pair have essentially the same energy

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